Question

g At a certain gas station, 30% of all customers use the restroom. What is the probability that, out of the next 10 customers, (a) exactly 4 will use the restroom

Answer 1

Answer:

$P(x=4) = 0.200$

Step-by-step explanation:

Given

$n=10$ --- selected customers

$x = 4$ --- those that are expected to use the restroom

$p =30\% = 0.30$ --- proportion that uses the restroom

Required

$P(x = 4)$

The question illustrates binomial probability and the formula is:

$P(x) = ^nC_x * p^x * (1 - p)^{n - x}$

So, we have:

$P(x=4) = ^{10}C_4 * (0.30)^4 * (1 - 0.30)^{10 - 4}$

$P(x=4) = ^{10}C_4 * (0.30)^4 * (0.70)^6$

$P(x=4) = 210* (0.30)^4 * (0.70)^6$

$P(x=4) = 0.200$